Hydrostatic systems include hydrostatic units, such as pumps, motors, and the like, and are often used in mobile hydraulic equipment and vehicles.
Hydrostatic units often have a variety of sensors such as pressure sensors, speed sensors, angle sensors, temperature sensors and the like. These sensors are wired to an electronic control box that controls the unit, or several units forming a hydrostatic system. The electronic control box may be mounted directly to the hydrostatic unit, to one or more of the several units forming the hydrostatic system, or may be installed remotely at another location inside the vehicle system.
Referring to FIGS. 1A and 1B, an exemplary hydrostatic unit 10 is shown having two pressure sensors 12 and one speed sensor 14. The pressure sensors 12 and the speed sensor 14 are wired to an electronic control box 16 through cables or wiring harnesses 18 that have connectors 20 facilitating the connection the sensors 12.
These cables or wiring harnesses 18 are difficult to handle in production and maintenance due to space and wire routing constraints, particularly as the usage of sensors around, upon and within hydrostatic units increases. The harnesses 18 are often obstructing access to parts of the host compartment and/or are in the way of other components within the engine compartment, which may cause the harnesses 18 and/or connectors 20 to be ripped off of the sensor 12 by accident. For example, FIG. 2 shows a picture of a hydrostatic unit 10 installed in a vehicle with arrows pointing to two sensors 12 of the hydrostatic unit.
The connectors 20 of the wiring harnesses 18 are a common source of reliability issues with hydraulic systems because the connections between the connectors 20 and sensors 12 need to be waterproof even against direct water for pressure from, for example, a high pressure washer, so that water-borne and solid contaminants that are common within the engine compartments of the vehicles, and equipment, in which the hydrostatic unit 10 is used, do not cause sensor failure. Dirt, moisture, extreme temperatures (−40° C. to +100° C.) and similar contaminants in engine compartments, where hydrostatic units 10 and systems are often housed and directly attached to an engine, are common to the environment. Thus, it is best if the connectors 20 remain as undisturbed as possible.
Additionally, an increasing number of sensors increases the number of wiring harnesses and connectors adding cost, in addition to the reliability issues.